Figure 13: Astral lobes: Original figure from Davies, 1932, p. 414.
AF: astral furrow (= foliar suture); AL (coloured): astral lobes (= folia): MB: marginal band (= keel); MF: marginal furrow (= septal suture); OC: outer chambers; P: pylome (= aperture); RF: radial furrows (= chamber sutures).